Allograft Augmentation of Hamstring ACL Autografts

is Associated with Increased Graft Failure

S. Clifton Willimon, MDMichael T. Busch, MD

Melissa A. Christino, MDBelinda Schaafsma, BSCrystal A. Perkins, MD

Children’s Healthcare of Atlanta

Background

• Rates of second ACL injury in adolescents have been reported to be as high as 37%1

• Numerous factors associated with ACL graft failure– Graft selection2-8

• Hamstring vs Patellar Tendon vs Quad Tendon• Autograft vs Allograft• Graft Diameter

– Patient age and activity level9-10

– Meniscal integrity11

Children’s Healthcare of Atlanta

Purpose

• To evaluate the association of soft tissue graft constructs and graft rupture following pediatric and adolescent ACL reconstruction.

Children’s Healthcare of Atlanta

Methods

Single center retrospective review• 2012 - 2016• 2 surgeons, same fixation and drilling techniquesInclusion criteria

– Age <20 years– Transphyseal or conventional drilling– Hamstring autograft +/- allograft augmentation

Exclusion criteria– Revision ACL reconstruction– Physeal sparing ACL reconstruction– Multiligament knee reconstruction– < 6 months clinical follow-up

Children’s Healthcare of Atlanta

Grafts

• 4-strand doubled semitendinosus + gracilis autograft

– 4-STG

• 5-strand tripled semitendinosus + doubled gracilis autograft

– 5-STG

• 6-strand doubled semitendinosus + gracilis autograft+ allograft augmentation

– 6-STGAllo

Children’s Healthcare of Atlanta

Demographics and Graft Failure

54% femaleAge range 10 – 19 years

Children’s Healthcare of Atlanta

Demographics and Graft Failure

Highest rate of failure with allograft-augmented grafts

Children’s Healthcare of Atlanta

Demographics and Graft Failure

Older age and larger graft sizes found in patients with allograft-augmented grafts

Children’s Healthcare of Atlanta

Predictors of Graft Failure

Graft rupture was associated with trends toward younger age and lower BMI

No association between graft rupture and graft size

Children’s Healthcare of Atlanta

Kaplan-Meier Survival Curve

Mean time to failure 16 months

Children’s Healthcare of Atlanta

Odds Ratios for Graft Failure

• Controlled for age and graft size

• An 8mm 6-strand allo-augmented graft has a 2.6 times increased risk of failure as compared to an 8mm 4-strand autograft

OR P-value6-STGAllo vs 4-STG 2.6 0.04

5-STG vs 4-STG 1.2 0.72

Children’s Healthcare of Atlanta

Conclusions

• High rate of graft failure following adolescent ACL reconstruction

• Hybrid hamstring autograft-allograft constructs have a significantly increased risk of graft rupture as compared to hamstring autografts

• 5-strand hamstring autografts with a tripled semitendinosus have equivalent failure rates to 4-strand autografts

• If a 4-strand autograft is “inadequate” in size, obtain a larger graft diameter by tripling the semitendinosus rather than augmenting with an allograft

Children’s Healthcare of Atlanta

Thank you

Children’s Healthcare of Atlanta

References

1. Allen MM, Pareek A, Krych AJ, et al. Are female soccer players at an increased risk of second anterior cruciate ligament injury compared with their athletic peers? Am J Sports Med 2016;44(10):2492-2498.

2. Bottoni CR, Smith EL, Shaha J et al. Autograft versus allograft anterior cruciate ligament reconstruction: a prospective, randomized clinical study with a minimum 10-year follow-up. Am J Sports Med 2015;43(10):2501-2509.

3. Burrus MT, Werner BC, Crow AJ et al. Increased failure rates after anterior cruciate ligament reconstruction with soft-tissue autograft-allograft hybrid grafts. Arthroscopy 2015;31(12):2342-2351.

4. Calvo R, Figueroa D, Figueroa F et al. Five-strand hamstring autograft versus quadruple hamstring autograft with graft diameters 8.0mm or more in anterior cruciate ligament reconstruction: clinical outcomes with a minimum 2-year follow-up. Arthroscopy 2016.

5. Darnley JE, Leger-St-Jean B, Pedroza AD et al. Anterior cruciate ligament reconstruction using a combination of autograft and allograft tendon: A MOON cohort study. Ortho J Sports Med 2016;47(7):1-5.

6. Parkinson B, Robb C, Thomas M et al. Factors that predict failure in anatomic single-bundle anterior cruciate ligament reconstruction. Am J Sports Med 2017.

7. Pennock AT, Ho B, Parvanta K et al. Does allograft augmentation of small-diameter hamstring autograft ACL grafts reduce the incidence of graft retear? Am J Sports Med 2016;45(2):334-338.

8. Jacobs CA, Burnham JM, Makhni EC, et al. Allograft augmentation of hamstring autograft for younger patients undergoing anterior cruciate ligament reconstruction: clinical and cost-effectiveness analyses. Am J Sports Med2016.

9. Ho B, Edmonds EW, Chambers HG et al. Risk factors for early ACL reconstruction failure in pediatric and adolescent patients: a review of 561 cases. J Pediatr Orthop 2016.

10. Kamien PM, Hydrick JM, Replogle WH et al. Age, graft size, and Tegner activity level as predictors of failure in anterior cruciate ligament reconstruction with hamstring autograft. Am J Sports Med 2013;41(8):1808-1812.

11. Magnussen RA, Lawrence TR, West RL et al. Graft size and patient age are predictors of early revision after anterior cruciate ligament reconstruction with hamstring autograft. Arthroscopy 2012;28(4): 526-531.